JPH0963228A - Disk cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a disk cartridge for a double-sided optical disk having interchangeability in shape with a disk cartridge for the existing single-sided optical disk. SOLUTION: A magneto-optical disk 2 is composed of cover glasses 4 and 6 of 0.6mm respectively, which are stuck on each other via a recording layer 7 formed between them to be capable of recording from both sides, and is fitted with hubs 8, each 1.2mm thick in the middle part on both sides. A case 3 for housing the magneto-optical disk 2 has such a structure that parts corresponding to the hubs 8 are opened by moving shutter plates 14 and 16, and a gap of 0.5-0.3mm is secured not to allow the hubs 8 to come in contact with the shutter plates 14 and 16, and then a dimension of K between inner walls of the case 3 is specified as 1.6-2.0mm, so that a space of 0.2-0.4mm from each surface of the magneto-optical disk 2 is secured not to allow the surface to come into contact with the inner wall of the case 3 even in the case of wobble of time surface, thus measuring dimensions of interchangeability in shape with the single-sided recording disk cartridge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc cartridge containing an optical disc capable of recording on both sides.

[0002]

2. Description of the Related Art As a known example of the prior art, a single-sided recording medium of 3.
There is a disk cartridge that houses a 5-inch magneto-optical disk. On the other hand, there is also a conventional example that proposes a disk cartridge capable of recording / reproducing information on both sides in order to increase the recording capacity.

For example, Japanese Patent Application Laid-Open No. 7-93934 discloses an optical disk device using an optical head dedicated to the A side and an optical head dedicated to the B side, and FIG. 1 shows a disc cartridge 21. An optical disc 23 having recording layers on both sides is housed inside. It is configured such that it is opened and closed by a shutter 24 that is integrated on both sides.

Further, in FIG. 4 of this publication, the thin portion 25a. 26a is formed,
The distance between the first optical head and the second optical head is smaller than the cartridge thickness T and larger than the optical disc thickness t.

[0005]

However, in this conventional optical disc apparatus, since the optical head dedicated to the A side and the optical head dedicated to the B side of the optical disc are arranged,
Optical disc 23 accommodated in the disc cartridge 21
Has a hub formed on only one side. That is, the disc cartridge 21 in which the optical disc 23 is stored
Can be used only in an optical disk device in which optical heads are arranged on both sides of the optical disk 23.

In the current optical disk device, the optical head is generally arranged only on one side of the optical disk. To use the double-sided optical disk for such a device, hubs are formed on both sides of the optical disk. There is a need to.
Considering compatibility, the disc cartridge that accommodates a double-sided optical disc with hubs formed on both sides should be approximately the same in shape as a disc cartridge that accommodates a single-sided optical disc that has a recording layer on only one side. In that case, it will be very effective.

In order to accommodate a double-sided optical disk, which is substantially the same in shape as an existing disk cartridge and has hubs formed on both sides, in the disk cartridge, the internal dimensions of the disk cartridge are specified and the shutter is released. The hub must not touch.

The present invention has been made in view of the above points, and an object thereof is to provide a disk cartridge for a double-sided optical disk, which is compatible in shape with an existing disk cartridge for a single-sided optical disk.

[0009]

A disk cartridge comprising an optical disk and a case that rotatably accommodates the optical disk, wherein the optical disk has a recording layer capable of optically recording and / or reproducing information from both sides. It has a cover glass having a thickness of 0.6 mm provided on both sides thereof and a hub having a thickness of 1.2 mm provided on both sides of the central portion, and the case has a dimension in the thickness direction of 6.0 mm, The optical disc is provided with a shutter that exposes a part of both recording surfaces of the optical disc and hubs on both sides, and the minimum dimension of the internal space for accommodating the optical disc in the thickness direction is 1.6 to 2.0 mm. The optical disc can be structured to be almost compatible with the existing single-sided optical disc, and the optical disc can be housed in a case that has almost the same external dimensions as the case for storing the single-sided optical disc. The houses are also secured clearance also can prevent contact with the shutter with respect to transportation or the like of the surface deflection and the disk cartridge when the optical disk rotation, and can avoid contact with the shutter and the hub.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments in which the present invention is applied to a disk cartridge which accommodates a 3.5-inch double-sided magneto-optical disk will be specifically described with reference to the drawings. 1 to 6 relate to an embodiment of the present invention, and FIG. 1 shows a front surface of a disk cartridge that accommodates a 3.5-inch double-sided magneto-optical disk according to an embodiment of the present invention. 1 shows the back side of FIG. 1, FIG. 3 shows a cross section taken along the line AA of FIGS. 1 and 2, FIG. 4 shows an example of fixing a hub to a magneto-optical disk, and FIG. 5 shows one embodiment. FIG. 6 shows the structure and dimensions of the main part of the disk cartridge, and FIG. 6 shows the configuration of the optical system of the magneto-optical disk drive according to one embodiment of the present invention. As shown in FIGS. 1 and 2, a disk cartridge 1 according to a first embodiment of the present invention is a 3.5-inch double-sided magneto-optical disk (hereinafter simply referred to as a double-sided disk).
The external dimensions are almost the same as those of the existing disc cartridge that accommodates the single-sided magneto-optical disc (hereinafter, simply referred to as the single-sided disc) 2 (of course, it is different from the structure of opening on both sides). The structure is such that a magneto-optical disk drive device compatible with the single-sided disk can be easily formed.

The disc cartridge 1 comprises a double-sided disc 2 and a case 3 for rotatably housing the double-sided disc 2. This double-sided disk 2 has a thickness of 0.6 mm and has a hole in the center as shown in FIG.
It is sandwiched between two disc-shaped cover glasses 4 and 6,
A recording layer (recording film) 7 capable of writing and reading information from both sides is provided.

Since the recording layer 7 is very thin, the thickness D of the double-sided disc 2 is determined by the two cover glasses 4 and 6 of 0.6 mm. That is, this thickness D is 1.2 mm, which is the same as the thickness of the existing single-sided disk (for a cover glass of 1.2 mm). An annular hub 8 made of a magnetic material is provided at the center of each of the cover glasses 4 and 6 by joining or the like. The hub 8 has an inner diameter Ri of 4 mm, an outer diameter Ro of 15 mm, and a thickness T of 1.2 mm.
The dimension H from the upper surface to the recording layer 7 is 1.8 mm.

The case 3 is a pair of rectangular case pieces 13 forming an internal space for rotatably housing the double-sided disk 2.
And fifteen. The dimension K (minimum between the inner walls) of the internal space formed by the case pieces 13 and 15 is 1.6 mm to 2. 1 which is 0.4 to 0.8 mm larger than the thickness D of the double-sided disc 2, ie 1.2 mm. It is set to 0 mm. In FIG. 2, the dimension K is 2.0 mm.

These are, for example, when the double-sided disk 2 is rotated on the spindle motor and when the double-sided disk 2 rotates, the surface run-out of the double-sided disk 2 during rotation, the transportation of the disk cartridge, and the like.
The dimension from each surface to the protrusion 11 is 0.2 to 0.4 mm (see FIG. 5) so as not to contact the protrusion 11 in the internal space formed by the case pieces 13 and 15. The dimension K'at the portion other than the protrusion 11 is the dimension K.
It is larger by the height of the protrusion 11 (K '= 2.2 mm when K = 2.0 mm).

As shown in FIG. 1, the case piece 13 is formed with an opening 9 for exposing the recording area on one side of the double-sided disk 2 and the hub 8. The case piece 15 is also shown in FIG. Thus, the opening 10 for exposing the recording area and the hub 8 on the other surface side of the double-sided disk 2 is formed.

The case 3 is provided with a shutter 12 for closing the openings 9 and 10. The shutter 12 has a shutter plate 14 that closes the opening 9 of the case piece 13 and a shutter plate 16 that closes the opening 10 of the case piece 15, and both are connected by a connecting member 18. This structure is a connecting member 18
Is assembled so as to be movable along the front surface 26 of the case 3, and the shutter plates 14 and 16 are biased by a spring (not shown) so as to move in a direction of closing the openings 9 and 10.

Further, the case pieces 13 and 15 have shutter restraining plates 22 and 2 for restraining the ends of the shutter plates 14 and 16, respectively.
4 is provided. Further, as shown in FIG. 3, the thickness U of the thin portion where the shutter plates 14 and 16 in the case 3 can move is 5.0 mm, and the thickness of the thick portions on both sides thereof (that is, the thickness of the disc cartridge 1). N is 6.0 mm.

On the front surface 26 of the disc cartridge 3,
A shutter opening pin fitting portion 28, into which a shutter opening pin of a magneto-optical disk drive (not shown) is fitted after opening the shutter 12, is provided. Further, on the front surface 26 of the disk cartridge 3, a projection portion 30 having an inwardly inclined surface is formed at an end portion on the side where the tip 20 of the connecting member 18 is located.
Is formed, and an inclined surface portion 32 having an inclined surface facing outward is formed at the opposite end.

The disk cartridge 3 is formed with semi-circular recesses 34 on both sides near the front surface 26 into which the cartridge fixing pins of the magneto-optical disk drive are fitted. The recess 34 penetrates the case pieces 13 and 15. Further, rectangular recesses 36 are provided on both rear side surfaces of the disc cartridge 3. Both the case piece 13 and the case piece 15 are formed with an alignment hole 38 and a positioning hole 40 into which a pair of positioning pins for horizontal positioning when the disk cartridge 3 is loaded in the magneto-optical disk drive are fitted.

Further, the case piece 13 has a positioning hole 40.
An erroneous erasure prevention mechanism 42 is provided behind the case piece 1 and
Similarly, an erroneous erasure prevention mechanism 44 is provided at the rear of the positioning hole 40 in the No. 5 as well.

As shown in FIG. 4, a metal material such as a ferromagnetic material is embedded in the hub 8, and a ring-shaped portion having a diameter larger than the outer diameter Ro of the hub is formed on the joint surface side with the double-sided disc 2. When it is fixed to both sides of the double-sided disk 2, it is pressed against both sides of the double-sided disk 2 as indicated by an arrow, and is fixed by fusion, bonding with an adhesive, or the like. in this case,
The dimension T of the hub 8 includes an annular portion. When the annular portion is not formed, it is the hub 8 itself as shown in FIG.

In this embodiment, the thickness D of the double-sided disc 2 is set to be the same as that of the existing single-sided disc, and the double-sided disc 2 is housed in a case 3 having almost the same size as the case for single-sided recording. FIG. 5 shows the structure and dimensions of the main part of the configuration described above (unit mm is omitted in the figure). As shown in FIG. 5, the thickness D of the double-sided disc 2 capable of recording on both sides is 1.2 mm.
The thickness of the single-sided disk is the same as that of the single-sided disk, and the internal space of the case 3 is defined so that the shutter plates 14 and 16 do not collide with the upper and lower surfaces of the hub 8.

First, the hub 8 has a thickness T of 1.2 mm as in the case of a hub formed on an existing single-sided disk, which enables cost reduction. Then, the shutter plates 14 and 1
6 so that the upper surface and the lower surface of the hub 8 do not collide with each other, the dimension K between the inner walls of the case 3 (that is, the minimum dimension of the inner space in the thickness direction) is set to 1.6 to 2.0 mm, and the shutter plate 14,
16 and the upper and lower surfaces of the hub 8 are 0.5 to 0.3 mm
The gap K is ensured, and the dimension K ensures a gap of 0.2 to 0.4 mm from each surface of the double-sided disc 2 so that the double-sided disc 2 can cope with surface deviation. It should be noted that one having a surface deviation of 0.2 mm or more on one side cannot be used for recording or reproducing high density information and is not used.

To further explain, the shutter plates 14 and 16
When securing a gap of 0.5 to 0.3 mm between the upper surface and the lower surface of the hub 8 and the hub 8, for example, as a better choice, 0.5
When it is set to mm, the dimension K is 1.6 mm. When the other selected value is 0.3 mm, the dimension K is 2.
It can be 0 mm.

With this setting, a space where the hubs 8 and the shutter plates 14 and 16 do not come into contact with each other is ensured, and a gap where the double-sided disk 2 does not come into contact with the inner wall of the case 3 due to surface wobbling is also ensured. According to the disc cartridge 1 having such a configuration and dimensions, the outer shape and dimensions thereof are almost the same as those of the existing disc cartridge that accommodates a single-sided disc. There is an advantage that the parts can be used as they are. Therefore, there is an advantage (effect) of being able to manufacture at low cost.

Further, since the gap between the double-sided disc 2 and the case 3 is made small, the thickness of the case 3 is the same as that of the existing disc cartridge containing the single-sided disc, and the thickness is increased. Since it does not exist, a small space is required even when a large number of disk cartridges 1 are stored.

Further, the magneto-optical disk drive side such as a loading mechanism for setting the double-sided disk 2 in a predetermined mounting state when the disk cartridge 1 is inserted from the insertion port is also common to the existing one-sided disk cartridge. The effect is great because you can increase the number of parts you can use.

Next, this double-sided disk 2 capable of double-sided recording
An optical system of a magneto-optical disc drive 51 capable of recording and reproducing on the disc cartridge 1 in which the disc is stored, and in the case of a disc cartridge storing an existing single-sided disc, will be described with reference to FIG. To do.

In the magneto-optical disk drive 51 shown in FIG. 6, an optical head 53 is arranged so as to face a single-sided or double-sided disk (indicated by reference numeral 52 here) mounted on a turntable. The optical head 53 includes a semiconductor laser 54 that emits a light beam, and a beam splitter 55 that splits the light beam into a disk 52 side and a photodetector side.
And the objective lens 5 that focuses the light beam on the disk 52.
6, a hologram 57 integrated on the semiconductor laser 54 side of the objective lens 56, a plane parallel plate forming an analyzer 58 by a crystal plate, a photodetector 59 divided into two, and adjacent to the photodetector 59. And a four-division photodetector 60 integrated with each other.

The photodetector 59 and the photodetector 60 are connected to a subtracter 61 and an adder 62 as shown in FIG. 2B, and a reproduction signal (abbreviated as MO signal) of the data portion of the magneto-optical recording is obtained. I am trying to get the playback signal.

Next, the operation of this optical system will be described. When the light beam emitted from the semiconductor laser 54 passes through the beam splitter 55 and enters the objective lens 56, the outer peripheral light of the hologram 57 and the O-order light of the hologram 57 converge on the cover glass having a thickness of 0.6 mm. Hologram 57
The primary light of (1) is converged 1.2 mm above the cover glass (shown by a chain double-dashed line).

That is, for example, when a CD ROM or a single-sided disk is inserted into the magneto-optical disk drive, information is recorded and reproduced by the light beam of the primary light of the hologram 57,
When the double-sided disk is inserted into the magneto-optical disk drive, information is recorded and reproduced by the outer peripheral light of the hologram 57 and the O-order light beam of the hologram 57.

The return light having the Kerr rotation component from the one-sided disc or the two-sided disc passes through the objective lens 56, is reflected by the beam splitter 55, passes through the analyzer 58, and is separated into ordinary light and extraordinary light. Is received by a photodetector 60 divided into four, and abnormal light is received by a photodetector 59 divided into two.

At this time, the focus error signal is detected by the astigmatism method with the ordinary light, and the tracking error signal is detected with the push-pull method with the abnormal light. The information signal is output from the adder 62 as a preformat reproduction signal for CDROM or magneto-optical recording, and the output from the subtracter 61 is a reproduction signal corresponding to the recorded information in the data portion for magneto-optical recording, that is, an MO signal.

In this embodiment, the hologram is integrally formed on the light source side of the objective lens, but two objective lenses (having different NAs and different focus positions) may be used. Furthermore, although the recording medium has been described using a magneto-optical medium, it is within the scope of the present invention to use a phase change recording medium. In that case, in the optical system shown in FIG. 6, it is necessary to dispose a quarter wavelength plate between the objective lens 56 and the beam splitter 55.

Although the optical system of the magneto-optical disk drive using the bifocal optical system has been described with reference to FIG. 6, a mechanism for shifting the mounting position of the recording medium such as the magneto-optical disk between the case of one side and the case of both sides is provided. It may be provided.

That is, with respect to the mounting position of the single-sided disc,
The double-sided disk is mounted at a position far from the objective lens by about 0.4 mm (when the cover glass has a refractive index of 1.5). By doing so, a magneto-optical disk drive capable of recording and reproducing in any case can be obtained.

The above-mentioned disc cartridge 1 is a write-once recording in the case of a disc-shaped optical recording medium capable of recording and reproducing such as a magneto-optical disc and a phase change recording medium for recording information by phase change. Type optical discs, read-only optical discs (CDROMs), and the like that contain a disc-shaped optical recording medium.

[0039]

As described above, according to the present invention, there is provided a disc cartridge comprising an optical disc and a case for rotatably accommodating the optical disc, wherein the optical disc optically records and / or reproduces information. A recording layer that can be used from both sides, a cover glass with a thickness of 0.6 mm provided on both sides, and a thickness of 1.2 m provided on both sides of the central portion.
m has a hub and the case has a thickness dimension of 6.0.
and a shutter for exposing a part of both recording surfaces of the optical disk and hubs on both surfaces of the optical disk, and a minimum dimension in a thickness direction of an internal space for housing the optical disk is 1.6 to 2.0 mm. Therefore, the optical disc can be structured to be almost compatible with the existing single-sided optical disc in external shape, and the optical disc can be housed in a case having substantially the same external dimensions as the case for housing the single-sided optical disc to prevent surface wobbling. It is possible to prevent the shutter from coming into contact with the shutter, and also to secure a gap that can avoid the contact between the shutter and the hub.

[Brief description of drawings]

FIG. 1 is a front view of a disk cartridge according to an embodiment of the present invention.

FIG. 2 is a rear view of the disc cartridge shown in FIG.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a cross-sectional view showing a hub fixed to a double-sided disc.

FIG. 5 is a sectional view showing the structure and dimensions of the main part of the disc cartridge.

FIG. 6 is a configuration diagram of an optical system of a magneto-optical disk drive that can be used in the disk cartridge of this embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Disc cartridge 2 ... Double-sided magneto-optical disc (double-sided disc) 3 ... Case 4, 6 ... Cover glass 7 ... Recording layer 8 ... Hub 9, 10 ... Aperture 12 ... Shutter 13, 15 ... Case piece 14, 16 ... Shutter plate 18 ... Connecting member 26 ... Front surface 30 ... Projection portion 32 ... Slope surface portion 34, 36 ... Recessed portion

Claims (1)

[Claims] 1. A disc cartridge comprising an optical disc and a case for rotatably accommodating the optical disc, wherein the optical disc is provided with a recording layer capable of optically recording and / or reproducing information from both sides and both sides thereof. A cover glass having a thickness of 0.6 mm and hubs having a thickness of 1.2 mm provided on both sides of the central portion, and the case has a dimension in the thickness direction of 6.0 mm, and both sides of the optical disc. 2. A disk cartridge comprising a shutter exposing a part of the recording surface and hubs on both surfaces, and a minimum dimension in a thickness direction of an internal space for housing the optical disk is 1.6 to 2.0 mm.